1/*	$NetBSD: hmac.c,v 1.5 2017/10/05 09:59:04 roy Exp $	*/
2
3/*-
4 * Copyright (c) 2016 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31#include <sys/cdefs.h>
32__RCSID("$NetBSD: hmac.c,v 1.5 2017/10/05 09:59:04 roy Exp $");
33
34#include <string.h>
35#include <stdlib.h>
36
37#include <md2.h>
38#include <md4.h>
39#include <md5.h>
40#include <rmd160.h>
41#include <sha1.h>
42#include <sha2.h>
43
44#define HMAC_SIZE	128
45#define HMAC_IPAD	0x36
46#define HMAC_OPAD	0x5C
47
48static const struct hmac {
49	const char *name;
50	size_t ctxsize;
51	size_t digsize;
52	size_t blocksize;
53	void (*init)(void *);
54	void (*update)(void *, const uint8_t *, unsigned int);
55	void (*final)(uint8_t *, void *);
56} hmacs[] = {
57	{
58		"md2", sizeof(MD2_CTX), MD2_DIGEST_LENGTH, MD2_BLOCK_LENGTH,
59		(void *)MD2Init, (void *)MD2Update, (void *)MD2Final,
60	},
61	{
62		"md4", sizeof(MD4_CTX), MD4_DIGEST_LENGTH, MD4_BLOCK_LENGTH,
63		(void *)MD4Init, (void *)MD4Update, (void *)MD4Final,
64	},
65	{
66		"md5", sizeof(MD5_CTX), MD5_DIGEST_LENGTH, MD5_BLOCK_LENGTH,
67		(void *)MD5Init, (void *)MD5Update, (void *)MD5Final,
68	},
69	{
70		"rmd160", sizeof(RMD160_CTX), RMD160_DIGEST_LENGTH,
71		RMD160_BLOCK_LENGTH,
72		(void *)RMD160Init, (void *)RMD160Update, (void *)RMD160Final,
73	},
74	{
75		"sha1", sizeof(SHA1_CTX), SHA1_DIGEST_LENGTH, SHA1_BLOCK_LENGTH,
76		(void *)SHA1Init, (void *)SHA1Update, (void *)SHA1Final,
77	},
78	{
79		"sha224", sizeof(SHA224_CTX), SHA224_DIGEST_LENGTH,
80		SHA224_BLOCK_LENGTH,
81		(void *)SHA224_Init, (void *)SHA224_Update,
82		(void *)SHA224_Final,
83	},
84	{
85		"sha256", sizeof(SHA256_CTX), SHA256_DIGEST_LENGTH,
86		SHA256_BLOCK_LENGTH,
87		(void *)SHA256_Init, (void *)SHA256_Update,
88		(void *)SHA256_Final,
89	},
90	{
91		"sha384", sizeof(SHA384_CTX), SHA384_DIGEST_LENGTH,
92		SHA384_BLOCK_LENGTH,
93		(void *)SHA384_Init, (void *)SHA384_Update,
94		(void *)SHA384_Final,
95	},
96	{
97		"sha512", sizeof(SHA512_CTX), SHA512_DIGEST_LENGTH,
98		SHA512_BLOCK_LENGTH,
99		(void *)SHA512_Init, (void *)SHA512_Update,
100		(void *)SHA512_Final,
101	},
102};
103
104static const struct hmac *
105hmac_find(const char *name)
106{
107	for (size_t i = 0; i < __arraycount(hmacs); i++) {
108		if (strcmp(hmacs[i].name, name) != 0)
109			continue;
110		return &hmacs[i];
111	}
112	return NULL;
113}
114
115ssize_t
116hmac(const char *name,
117    const void *key, size_t klen,
118    const void *text, size_t tlen,
119    void *digest, size_t dlen)
120{
121	uint8_t ipad[HMAC_SIZE], opad[HMAC_SIZE], d[HMAC_SIZE];
122	const uint8_t *k = key;
123	const struct hmac *h;
124	uint64_t c[32];
125	void *p;
126
127	if ((h = hmac_find(name)) == NULL)
128		return -1;
129
130
131	if (klen > h->blocksize) {
132		(*h->init)(c);
133		(*h->update)(c, k, (unsigned int)klen);
134		(*h->final)(d, c);
135		k = (void *)d;
136		klen = h->digsize;
137	}
138
139	/* Form input and output pads for the digests */
140	for (size_t i = 0; i < sizeof(ipad); i++) {
141		ipad[i] = (i < klen ? k[i] : 0) ^ HMAC_IPAD;
142		opad[i] = (i < klen ? k[i] : 0) ^ HMAC_OPAD;
143	}
144
145	p = dlen >= h->digsize ? digest : d;
146	if (p != digest) {
147		memcpy(p, digest, dlen);
148		memset((char *)p + dlen, 0, h->digsize - dlen);
149	}
150	(*h->init)(c);
151	(*h->update)(c, ipad, (unsigned int)h->blocksize);
152	(*h->update)(c, text, (unsigned int)tlen);
153	(*h->final)(p, c);
154
155	(*h->init)(c);
156	(*h->update)(c, opad, (unsigned int)h->blocksize);
157	(*h->update)(c, digest, (unsigned int)h->digsize);
158	(*h->final)(p, c);
159
160	if (p != digest)
161		memcpy(digest, p, dlen);
162
163	return (ssize_t)h->digsize;
164}
165